“What a silly question!” you might be thinking. “Of course, the answer is one!” (Unless, of course, in the case of fraternal twins, when two eggs must’ve snuck through.)

Well, you’re halfway right. You ovulate one egg per month, usually. This is the single egg that makes it through the whole ovulatory process: the egg follicle is activated, the egg grows and matures, and then—once it reaches maturation—it breaks free from the ovary and begins on its journey down the Fallopian tubes. That’s ovulation (and the plot of like, a million coming-of-age films about road-tripping teenagers).

But the fact is that there are tons of other eggs that don’t make it past that first stage. Each cycle, maybe 15–20 follicles are activated, but when they don’t mature, they get “reabsorbed” (AKA, they die). This process is called “atresia.”

And then—to make matters even worse—doctors estimate that we lose up to a thousand additional follicles each month, thanks to natural cell death. If you’re counting, that’s up to 1,021 eggs lost each month. Even if you’re pregnant, on birth control, or otherwise not ovulating. And the number lost each month accelerates as you age.

The good news is that egg freezing makes use of some of those otherwise “lost” eggs. The egg freezing process uses hormone medication to step up the action in your ovaries, prompting them to produce multiple mature eggs instead of the usual one, so you can freeze them for when—or if—you might need them.

Want to know more about how it works? Check out the Extend Fertility egg freezing process!